The invention concerns a transport system of the dual-mode type comprising dual-mode vehicles and a monorail, said dual-mode vehicles being capable of running both on an ordinary roadway and as rail vehicles on the monorail. The monorail has a substantially triangular cross-sectional profile with one apex of the triangle facing upwards, and each of the vehicles has a downwards-facing, through-going indentation extending in the longitudinal direction with a cross-sectional profile which corresponds substantially to the cross-sectional profile of the monorail. Each vehicle has drive-wheels for running on the roadway and drive- and support-wheels for running on the monorail.
From international patent application no. PCT/DK91/00146 (WO 91/18777) a transport system of the kind described in the introduction is known, where dual-mode vehicles can run on the substantially triangular rail individually or as coupled together units, and also as individual vehicles on an ordinary roadway.
With this reference, everything otherwise disclosed in the above-mentioned application forms part of the present application.
The main component in this known transport system, which transport system is also referred to as the RUF system, is the vehicle 1, which is shown in FIGS. 1 and 2 of the drawing, running either on a rail 2 with a substantially triangular cross-sectional profile 7, or on a roadway 10, in that each vehicle has ordinary drive-wheels 8 for this purpose.
Each vehicle has a front end and a rear end which are configured so that two or more vehicles can be expediently coupled together during running on the rail, and in such a manner that the aerodynamic characteristics of the vehicles are taken into consideration, both individually as well as when coupled together. For example, the vehicles shown in the above-mentioned international patent application are configured in such a way that the front end has two substantially plane surfaces 3 and 4 which meet along a horizontal line 5, and where the rear end has two substantially plane surfaces 3xe2x80x2 and 4xe2x80x2 which similarly meet along a horizontal line as shown and, moreover, as explained in the above-mentioned international application. Several vehicles can hereby be expediently coupled together during running on the rail, as shown in FIG. 1.
In FIG. 2 it is seen how the dual-mode vehicle 1 is transferred from running on the rail 2 out to the roadway 10 as an independent electric vehicle on wheels 8, in that the vehicle can thus be supplied with current from batteries carried by the vehicle.
The vehicle also has a downwards-facing, through-going indentation 6 in the longitudinal direction which has a cross-sectional profile corresponding substantially to the cross-sectional profile 7 of the rail.
With the prior art, the monorail is provided with a special braking-rail 9 at the top of the monorail 2, such as shown in FIG. 1, in that a braking arrangement with brake shoes (not shown) can be pressed towards this braking-rail 9. Furthermore, the vehicle of the known configuration has a driving-wheel (not shown) which generates the driving power for rail running, in that it is placed in such a manner that it transfers the propelling force to a substantially horizontal surface on top of the monorail 2. The vehicle of the known configuration also has wheels (not shown) which support the vehicle on the rail 2, in that these support wheels run on inclined side surfaces of the triangular monorail 2, and are thus arranged with their axes of rotation at an angle in relation to the horizontal.
It is the object of the invention to achieve an increase in the driving force which is transferred from the vehicle to the monorail when the vehicle is running on the rail.
As disclosed in the characterising portion of claim 1, this is achieved in that the vehicle has at least two drive-wheels for rail running, said drive-wheels being arranged with the axis of rotation substantially vertical, and such that for running on the rail at least one drive-wheel is placed on each side of a substantially vertical surface of the monorail.
At least two drive-wheels can hereby be pressed towards each other and together around the substantially vertical surfaces of the monorail, so that the friction between drive-wheel and the rail can be increased in comparison with the prior art. With the prior art, where the drive-wheel is arranged in a vertical plane so that it presses vertically down against the monorail, the friction will actually be limited, in that the friction is defined by the force of gravity. With the invention, it will be possible to increase the friction, and herewith the force which is transferred, by increasing the force with which the drive-wheels are pressed against the monorail and towards each other, and it will also be possible to adjust the pressure in accordance with the actual need. The pressure against the monorail can thus be increased when the vehicle is running upwards, accelerating and/or running with heavy loads. Correspondingly, the pressure can be reduced in stable running situations, i.e. at constant high speed and with level running, also when running downwards and/or when the speed is reduced. The friction losses are hereby minimised, in that energy is not wasted by unnecessarily high friction.
Moreover, with the invention it is possible for use to be made of substantially vertical surfaces of the monorail for propelling the vehicle, and such that problems will not arise with operational disturbances such as loss of friction in the event of ice formations and snowfall, and layers of water will not be able to lie on the drive surfaces in rainy weather.
Finally, with the invention the rail drive-wheels can be used to brake the vehicle when running on the rail, in that also here it is utilised that the friction and herewith the braking power can be adjusted. Moreover, this can be utilised with regenerative running, where electrical energy is generated in the vehicle when it is braked, in that this regenerative braking-down can be optimised by means of the adjustable friction.
It can be expedient that the substantially vertical drive surfaces, as disclosed in claim 2, be comprised of a driving rail which is placed on top of the monorail.
Moreover, as disclosed in claim 3, the vehicle can have a set of support wheels which are arranged with their axes of rotation substantially horizontal or at an acute angle in relation to the horizontal, and where the monorail has corresponding support surfaces. The vehicle will hereby be supported more effectively on the monorail than with the known arrangement, where the support wheels are arranged with their axes at an angle of around 45xc2x0-60xc2x0 in relation to the horizontal. When the support surfaces are arranged in a slightly sloping manner, it is achieved that rainwater and the like can run off, and moreover a correcting effect on the vehicle is achieved, so that this is positioned correctly in relation to the centre of the monorail.
Furthermore, as disclosed in claim 3, the angle in relation to the horizontal can be varied along the monorail, so that the correcting or xe2x80x9cself-centringxe2x80x9d effect along the rail is varied. For example, this can be utilised in such a manner that at the beginning of a monorail, where the vehicles run up on the rail, the angle is relatively great, so that there is a great correcting effect, in that at this point it is necessary to get the vehicle positioned correctly in relation to the rail relatively quickly before the vehicle picks up speed. In connection herewith, the angle of the axes of rotation for the support wheels in relation to the horizontal can be made greater than during normal operation, when a vehicle begins to run up on a rail and during the first part of the running on the rail, so that the angle of the support surfaces and the angle of the support wheels match each other, whereby the self-correcting effect is increased. For example, this can be effected while utilising the fact that during this part of the running, the rail drive-wheels will not be in a position where they are moved towards the centre of the vehicle, but away from a driving rail""s position in the vehicle. The suspension of the support wheels can thus be connected to the suspension of the rail driving-wheels in such a way that, in this situation, the support wheels will be placed with a greater angular inclination than in the normal running position, while when the rail drive-wheels are pressed in against the driving-rail in a normal running position, the support wheels will lie in the normal angular position for running on the rail.
Moreover, the monorail can be configured so that the angle of its support surfaces will be relatively great around bends and other places where there is a risk that the vehicle can be influenced away from the correct position in relation to the rail, so that also here a great self-correcting effect is achieved. In other places where the vehicle is run at constant speed and/or direction, the angle of the support surfaces can be made relatively small.
As disclosed in claim 4, the said support surfaces can expediently consist of support rails which are placed at the bottom of and on each side of the monorail.
In that the support wheels are intended to run on the rail""s support surfaces, which unlike an ordinary road can not be uneven, bowed or pitted, but will be even, there will not be any need for the same degree of spring suspension as with roadway wheels. The same will apply for the rail drive-wheels. As disclosed in claim 5, it can thus be expedient to use wheel motors in the rail drive-wheels or the support wheels. The use of wheel motors, i.e. motors, especially electric motors which are built directly into the wheels, is not to be found to any great extent in connection with vehicles for running on ordinary roads, in that auxiliary motors increase the un-suspended weight of the wheels, which is a great disadvantage with wheels which, as is normal for roadway wheels, have a high degree of spring suspension. Since the rail wheels do not require any high degree of suspension, the use of auxiliary motors can thus be of advantage.
As characterised in claim 6, it can be expedient to place auxiliary motors in a support wheel or a rail drive-wheel on each side of the vehicle, in that a transfer of power is established from each support wheel to each rail drive-wheel. In a suitable manner, a suitable placing of the driving power for the rail drive-wheels is hereby achieved, while at the same time both the support wheels and the rail drive-wheels are supplied with driving power. Moreover, the vehicle can hereby be suitably arranged so that it is the support wheels which, under normal circumstances, transfer driving power to the monorail, while the rail drive wheels are in engagement with the drive-rail only in special situations, such as during acceleration or on gradients, when running up on the rail at the beginning of the rail, under heavy loads, when braking-down, when running under slippery conditions etc., so that loss of friction, wear on components and the like are limited as much a possible.
Moreover, as disclosed in claim 7, it can be expedient to provide for a transfer of power from a support wheel, which is provided with an auxiliary motor or which in itself is driven by an auxiliary motor in a rail drive-wheel, to a drive-wheel for running on roadways. In an advantageous manner, there is hereby achieved a supply of driving power to the roadway wheels while making use of the driving power for rail running which is already installed in the vehicle.
With a suitable embodiment, such as disclosed and characterised in claim 8, each of the at least two driving rail wheels can be suspended in a special support arrangement which is pivotally suspended in the opposite side of the vehicle in relation to the relevant rail drive-wheel, and in such a way that the support arrangement can be turned a greater or smaller angle between two outer positions, where the rail drive-wheel is in power-transferring contact with the drive surface on the monorail. A self-clamping effect is hereby achieved, in that the tractive power of the rail drive-wheels in combination with the reaction of the support arrangement will result in the rail drive-wheels pressing harder against the rail surfaces when tractive power is applied. Similarly, when the rail drive-wheels are used for braking, these will be pressed harder against the rail surfaces where braking power is transferred.
Since the rail drive-wheels and/or the support wheels, as mentioned earlier, run solely against completely plane and even rail surfaces, it can be expedient to use coatings of firm materials, for example hard rubber coatings, as disclosed in claim 9, instead of inflatable rubber wheels, whereby disadvantages such as puncturing etc. in connection with inflatable rubber wheels can be avoided when running on rails, thus increasing the operational security.
As characterised in claim 10, a further improvement can be obtained by configuring the rail drive-wheels and/or support wheels with driving surfaces of metal, in that the operational security is hereby increased. In this connection, the rail surfaces can be of metal or have a coating of a material with a certain flexibility. When the rail surfaces instead of the wheels are provided with e.g. a rubber coating, an increase in security is achieved, in that it will not be the user of the individual vehicle who must ensure that the rubber coatings on the wheels are intact, but the operator, who has overall responsibility for the system, who must ensure that the rail wheel function is in order, including that the rubber coatings on the rail are in place and intact.
Furthermore, with such flexible coatings, e.g. firm rubber coatings, it is possible for the friction along the drive-rail to be graduated, so that in places were good friction is required, such as on gradients and during acceleration, use can be made of a coating with a very high friction, while in places without gradients or accelerations etc. where running conditions are normally stable, use can be made of a coating with low friction, so that loss of friction during running is limited as much as possible, while at the same time optimum conditions of propulsion are achieved. In places where there is only need for low friction, a coating can possibly be dispensed with, in that the material of the metal drive rails can here constitute the driving surfaces.
Finally, with this embodiment, where there are flexible coatings on the rail surfaces, it is achieved that a possible coating of ice, e.g. in the event of ice-glazing, will be shattered by the pressure of the metal wheels against the flexible coating. Such a possible coating with ice will thus be shattered by the leading wheels of a vehicle and will trickle down, after which the rear wheels on the vehicle will roll on a clean surface.
In the following, the invention will be explained in more detail with reference to the drawings, where
FIG. 1 shows a known dual-mode vehicle arranged as both rail vehicle and roadway vehicle,
FIG. 2 shows the vehicle shown in FIG. 1 during the transitional phase from rail running to roadway running,
FIG. 3 is a sketch showing the main components forming a dual-mode transport system according to the invention, seen from the front, and
FIG. 4 shows a suspension, seen from underneath, for the rail drive-wheels in an embodiment of a transport system according to the invention,